Panasonic ST-CH7L User manual

ORDER NO. AD9104083C8
Service Manual
LW/MW/FM
Stereo
Tuner
Tuner
Color
(K) e250
inf
Black
Type
Areas
Country
Code
(E) Continental Europe.
Asia, Latin America,
Middle Near East and
Africa.
Because of unique interconnecting cables,
when a component requires service, send or
bring in the entire system.
Oceania.
System: SC-CH7
@ SPECIFICATIONS
(DIN 45 500) Sensitivity (S/N 20 dB)
MW 20 uV, 300 pV/m
m@ FM TUNER SECTION LW 50 pV
Frequency range 87.50~108.00 MHz (0.05 MHz step) Selectivity (+9 kHz)
Sensitivity 1.5 uV (IHF, usable) MW (at 999 kHz) 50 dB
S/N 30dB 1.5 wV (75Q) LW (at 216 kHz) 50 dB
S/N 26 dB 1.3 pV (75Q)
S/N 20dB 1.2 pV (75Q) m TIMER SECTION
IHF 46 dB stereo quieting sensitivity 28 pV (750) Clock Quariz-lock type
Total harmonic distortion 24-hour indication
MONO 0.2% Functions 24-hour programmable;
STEREO 0.3% weekly (1 time)
S/N once only (1 time)
MONO 60 dB (74 dB, IHF) sleep (1~120 min., 1-min. intervals)
STEREO 58 dB (70 dB, IHF) Setting intervals 1 minute~23 hours, 59 minutes
Frequency response 20 Hz~15 kHz, +0.5 dB~—1.5 dB (at 1 min. intervals)
Alternate channel selectivity +400 kHz 50 dB
Stereo separation 1 kHz 40 dB @ GENERAL
10 kHz 30 dB Power consumption 8W
Channel balance (250 Hz~6,300 Hz) +1.5dB Dimensions (WxHxD) 215x55x295 mm
Limiting point 1.2 UV (815/s2" x 252" x 115%")
Bandwidth Weight 1.4kg (3.0 Ib.)
IF amplifier 180 kHz
FM demodulator 1000 kHz Notes:
Antenna terminal 75Q (unbalanced) 1. Total harmonic distortion is measured by the digital spectrum
analyzer.
@ LW/MW TUNER SECTION 2. Specifications are subject to change without notice.
Frequency range 3. Weight and dimensions shown are approximate.
MW 522~1611 kHz (9 kHz-step)
530~ 1620 kHz (10 kHz-step)
LW 144~288 kHz (9 kHz-step)
146~290 kHz (+2 kHz-shift)
System [Tuner | —sAmplifier_—_—| CD Player Cassette Deck Speakers
SC-CH7 ST-CH7L SU-CH7 SL-CH7 RS-CH7 SB-CH7
‘Technics /Panasonic
(E) (GC) (GN)

ST-CH7L
m@ CONTENTS
Page
LOCATION OF CONTROLS ........... 0.00 0c cece e eee eens 2,3
DISASSEMBLY INSTRUCTIONS ................000 000 eee 4
MEASUREMENTS AND ADJUSTMENTS .................. 5,6
DESCRIPTION OF FLPANEL ...............000cceeeeeees 7
FUNCTION OF IC TERMINALS..............0.00.0 00. ce ees 8
SCHEMATIC DIAGRAM ..............000 cc ccc eee e eee 9~12
Note:
Page
PRINTED CIRCUIT BOARDS AND WIRING CONNECTION
DIAGRAM (., 55355 05te chen fon oi wate Saitonae nae oe 13, 14
BLOCK DIAGRAM ..........0.. 00. c cece eee e eee 15, 16
REPLACEMENT PARTS LIST ..................0.000, 17~21
CABINET PARTS LOCATIONS ............0 0000 cece cee ues 21
Refer
to
the
service
manual
for
Model
No.
SU-CH7,
Order
No.
AD9104082C8
for
information
on
ACCESSORIES,
INSTALLATION
OF
THE
SYSTEM,
CONNECTIONS
and
PACKAGING.
m@ LOCATION OF CONTROLS
SENSOR
CANCEL RECALL CLOCK SET
WSELECT A
© Oo
G
STEREO SYNTHESIZER TUNER ST-CH7L
om MWV ALLOCATION PT
LW FREQ sine
PRESET
Tuner: control section
@ Timer set button (TIMER SET)
This button is used when making the timer setting.
Timer select buttons (WV SELECT A)
These buttons are used when setting the time. And when
making the timer setting, to select the type of timer operation,
the day, the time, etc.
@®
Remote signal sensor (SENSOR)
Band select button (BAND)
This button is used to select either the MW, LW or FM band.
Preset-tuning buttons (V PRESET A)
These buttons are used to select channel numbers for a
broadcasting station which has been stored in the tuner’s
memory.
®
®
© Timer cancel button (CANCEL)
This button is used to cancel the timer setting.
Power “STANDBY ()/ON” switch
(POWER STANDBY (!) /ON)
This switch switches ON and OFF the secondary circuit power
only. The unit is in the “standby” condition when this switch is
set to the STANDBY (' position. Regardless of the switch
setting, the primary circuit is always “live” as long as the
power cord is connected to an electrical outlet.
@
©
Timer setting confirmation button (RECALL)
This button is used to confirm the timer setting.
Clock set button (CLOCK SET)
This button is used to set the present time.
Memory button (MEMORY)
This button is used when presetting broadcast station
frequencies into memory.
Tuning
buttons
(V
TUNING
A)
These
buttons
are
used
for
tuning
the
desired
broadcast
Station.
@ ©
@

SENSOR
ST-CH7L
Tuner: display section
@
©
© 86 ® &® @®
Timer play/recording indicator (PLAY, REC)
This indicator shows that timer play mode or timer recording
mode is activated.
Timer mode-indicator (] ONCE, WEEKLY)
This indicator shows the timer operation mode (ONCE or
WEEKLY).
Day display (SUN—SAT)
This display shows the present day, or the day the timer has
been set for, if used.
Sleep indicator (SLEEP)
llluminates when the sleep timer is activated.
Timer ON/OFF indicator (ON, OFF)
This indicator shows whether the times for timer switch-ON
and switch-OFF have been set.
Time display
This display shows the present time, or the time the timer has
been set for.
FM stereo indicator (STEREO)
This indicator automatically illuminates when an FM stereo
broadcast is being received. It will not illuminate if the FM
mode button is used to select monaural mode.
®
® O08 8 O
Band indicator (FM, MW, LW)
Illuminates to show which band is selected.
Digital frequency display
Displays the broadcast frequencies.
Quartz lock indicator (QUARTZ LOCK)
This indicator illuminates when the unit is precisely tuned to a
broadcast station.
Memory indicator (MEMO)
This indicator illuminates when the memory button is pressed.
Preset channel display
This display shows the channel number selected by the
preset-tuning buttons.
FM mode indicator (AUTO, MONO)
When FM broadcasts are being received, usually the “AUTO”
indication is illuminated. When the FM mode is set to
monaural, “MONO” illuminates.

ST-CH7L
m@
DISASSEMBLY
INSTRUCTIONS
“ATTENTION SERVICER”’
Some
chassis
components
may
have
sharp
edges.
Be
careful
when
disassembling
and
servicing.
aa] Removal of the Cabinet
1
Remove the 5 screws (@~@).
Procedure
1523
Pee
||
Removal
of
the
Operation
P.C.B.
Front Panel
Reinforce plate
1.
Remove
the
2
screws
(@, @).
1.
Puilup
the
position
©
of
the
front
panel
in
the
direction
of
the
2.
Remove
the
front
panel
in
the
direction
of
arrow.
arrow
@,
and
then
remove
the
reinforce
plate
in
the
direction
of
the
arrow
©.
*Remove
the
8
screws
(@~@).

ST-CH7L
ST-CH7L
m MEASUREMENTS AND ADJUSTMENTS
This TUNER (ST-CH7L) is powered by the amplifier (SU-CH7). To adjust it or check operations as a separate unit,
follow the steps below.
1. Apply a power supply voltage of AC 23 V to [yZe and iZey)-
2. Power supply switch: ON
HOW TO CONNECT
Note:
Apply a power supply voltage of AC 23 V
to pieydehd and paeygeyy by using a Voltage
Controller. If itis not available, use a
Power Supply Fixture
(SZZA1058C)
Voltage controller
Power Supply Fixture (SZZA1058C) OR
instead. © a
e ADJUSTMENT POINT
AM
LOOP
ANT
AM
ANT FM ANT TO AMP
750
7
Z202 LINE OUT LINE OUT
(Leh) (Reh)
FM mono
distortion
FM offset
PLL clock Frequency
FM MPX VCO
(I9kHz)
eFM ADJUSTMENT
Control positions and equipment used
@FM signal generator (FM-SG)
Frequency counter
Choke coil (100 LH)
e Resistor (100 kQ)
Stereo modulator
e Distortion analyser
DC electronic voltmeter (EVM)
Note: For Z201 (AM ANT and OSC coil), Z202 (AM-IFT), they are supplied as adjusted parts. So, do not turn the cores of the parts.
If is not necessary to adjust the AM circuit.
FM OFFSET VOLTAGE AND MONO DISTORTION
ADJUSTMENT FM SIGNAL GENERATOR CONDITION
Modulation
1. Test equipment connection is shown in figure. Modulation frequency
. Set the unit to “FM” mode. Output level
. Set the radio frequency display and signal generator to
100.10 MHz.
. Adjust the core of T201 so that the voltage measured in signal
mode is 0 mV (0+20 mV) in 300 mV range.
. Adjust T202 so that the distortion factor of L-CH and R-CH is
minimized.
. Repeat steps 4 and 5.
Note: The adjusting screwdriver used should be made of resin.
FM MPX VCO ADJUSTMENT
. Test equipment connection is shown in figure.
. Set the unit to “stereo” position.
. Set the radio frequency display and signal generator to
100.10 MHz.
. Adjust VR501 for 19 kKHz+30 Hz on frequency counter reading.
FM ANT (759)
USING ALTERNATE SYSTEM
1. Receive the stereo broadcast.
2. Adjust VR301 until stereo indicator lights up. Fix the arm of
VR301 as shown in gifure. “Stereo”
FM SIGNAL GENERATOR CONDITION
Modulation
Modulation frequency .... OkHz
Output level
. “Stereo” OFF position
. “Stereo” ON position
(Indicator lighting)
Adjust point of pilot circuit
PLL CLOCK FREQUENCY ADJUSTMENT
Use a high impedance probe.
Frequency counter
1. Test equipment connection is shown in figure.
2. Adjust CT101 for 2070+0.010 kHz (2050+0.010 kHz...GC only)
on frequency counter reading.

9 O00000
’
=
“requency counter
*)
1
a
sis
circuit
requency counter
(ar)
i
As
ST-CH7L
m@ DESCRIPTION OF FL PANEL [FL901 (RSLO096-F)]
eGRID ASSIGNMENT
7G
SUN MON TUE WED THU FRI SAT
ONCE WEEKLY PLAY REC SLEEP
QUARTZ LOCK 20 1
kHz Memo 2alé chsh auto
cH.el_lé el_le
@PIN CONNECTION
3/3l2l2f2j/2t2;2l2j2i2l2ajiliaiaiatiasaia}ata}a
PIN NO. 110/9/8/7/6/5/4/3/2/1]/o0/9/81/7/6/5/4/3/2]/1]ol9;8|7\/6/5/4/3]/2]1
FIF P|P/P/P/PIP|P|Pj/P/P|PIP|P|P|P|P|P N/FIE
CONNECTION qiq}qtatadd 1IN/1/2/3/4/5/6/7
2/2 7/5/4/3/2]1lol9lslol1j2i3l4islel6élcialalalalaiala/pi1]41
Note: 1) F1,F2.............. Filament
2) INP cricstsacicdta Siateboestr No pin
3) 1G~8G ............ Grid
@ ANODE CONNECTION
AM
— PM 2e FM 2e | 2e
WEEKLY 2c 2c
_ _ 2g MW 29
ONCE — of — 2t 2f
—_ 2b 2b — 2b 2b
+ = i a
2a, 2d, 2e, 2g 2a STEREO 2a 2a
PLAY ON col $1 2h 2h
2d
2a, 2d, 2e, 2g
AUTO
QUARTZ LOCK
P8 WED 1d 1d
P9 SAT le le
P10 in TUE 1c 1c
i Pit FRI 1g 1g
P12 MON zi 1f
P13 THU 1b
P14 SUN la
Pts nn
P16 -_ —
ST-CH7L
m FUNCTIONS OF IC TERMINALS
@|C901 (MN187125STT1)
——
Pin He) : Pin Vo :
No. Mark Division Function No. Mark Division Function
1 VDD I Power supply (+B) 22 SBT1 O Clock terminal for serial data.
: OSCE Connected to crystal oscillator 23 CE ie) aie Hensiniesion Operation
(X901) (4.19 MHz) ip enable terminal
3 Osc O :
24 SBO1 ie) Serial data signal output
Connected to ground terminal
BoC OUE 2 External control clock signal input-
output
Connected to ground terminal
26 | CLOCKIN
X0 Not connected
DATA OUT
External control data signal output
7 KEY2 I Key scan signal input
Not connected
8 | KEY1 BIN I Connect to ground terminal
a I Connectd to ground terminal
9 CR | Not connected
-——————_-—-— sch OT DATA IN | External control data signal input
Stereo input
10 STEREO I Inputs when stereo signal receipt Input for stop signal during auto
“L”, monaural signal receipt “‘H”’. tuning.
—S Stops auto tuning at high level.
When broadcasting receipt “L”, Receipt: H, No signal: L
14 DIR | stereo/normal broadcasting
receipt “H”. Output for erasing shock noise
Not connected when lock-off at PLL.
bt} <Muting outut>
12 MONO oO Auto/mono change over terminal. 1. Power switch “off”.
2. Frequency change
13 MERO O Remote control signal terminal. (up/down, FM<—>AM<—> TV)
14 Not connected Put out “H” when those of above
two.
15 INT | Remote control input
16 peas l Power supply level detection Netcoanecied
oe DTS selective output terminal. .
oO Key scan signal output
wt Not connected
BM
AC output
Put out for “H’” when moving. For Digit signal output to FL display
cutting relay dirive of main power
3 POWER o supply. Becomes “H” when PLL is
moving. Reverse when put the
power key.
20 TB I Band data input
Reset signal input
21 RESET l Input of reset for micro computer
stand
Serial data signal input
Segment signal output to FL
display
FL motor power supply

| SCH EMATIC DIAG RAM (Parts list on pages 17~20.)
Notes:
eS901,902 : Preset channel switch.
(S901: Up, S902: Down)
eS903 : Band select switch.
eS904 : Memory switch.
eS905, 906 : Tuning switch.
(S905: Up, S906: Down)
eS907,908 : Timer select Switch.
(S907: Up, S908: Down)
eS909 : Timer set switch.
@S910 : Clock set switch.
eS9i1 : Timer setting confirmatin switch.
e$912 : Timer cancel switch.
eS913 : Power switch.
indicated voltage values are the standard values for the unit measured by
the DC electronic circuit tester (high-impedance) with the chassis taken as
standard. Therefore, there may exist some errors in the voltage values,
depending on the internal impedance of the DC circuit tester.
(_ ): MW voltage, [ ]: LW voltage, ]: MUTING voltage
eimportant safety notice
Components identified by A. mark have special characteristics important
for safety. When replacing any of these components, use only
manufacturer's specified parts.
eThis schematic diagram may be modified at any time with the
development of new technology.
ooo00f FMOSC
muaep AMOSC
«Caution!
a>
IC and LSI are sensitive to static electricity.
Secondary trouble can be prevented by taking care during repair.
AM signal
AF signal lines
*Cover the parts boxes made of plastics with aluminum coil.
*Ground the soldering iron.
*Put a conductive mat on the work table.
«Do not touch the legs of IC or LSI with the fingers directly.
Positive voltage lines --=—=— Negative voltage lines
c—> FM signal
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m@ BLOCK DIAGRAM
ST-CH7L
ST-CH7L
—15—
~16—
(5 Pee ees
JK7O
FM
MONO
DISTORTION
adj.
RMI
ALSS2E
0302
c
amp
eek
FM
MPX
D302
o
9
T201,202
ANT273W
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FM ANT 7; 7H ® 8
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VCO adj) | SSK
Buffer
(>
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;
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Q256
Signal
receive
detector
XIOl
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(72MHz)
D201
z901
LM7OOI }
_
REMOTE
Spd7te3ds
Licio1)
CONTROL
~
PLL
FREQUENCY
control
SENSOR
(AM)
@B)
FM/AM
XOUT
XIN
LW
PD2
FMIN
SYNTHESIZER
Power Supply Shem AM IN
(FM) GB) Selector
Vss TB CE CL DATA
~ Fe 7 $3 94 FO
Switching
(reset)
|
907,908
KEY
MATRIX
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STEREO
MONO
INT
POWER
Q902~905
KEY2 DOWN
\(APRESET)
(ATUNING)
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DATA
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$904
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'AM SIGNAL |
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Rech out
Lech out
POWER
B.CLK
B.DATA
B. GND
Ac
Ac

m REPLACEMENT PARTS LIST
ST-CH7L
ST-CH7L
Notes :
* Important safety notice:
Components identified by A\ mark have special characteristics important for safety. When replacing any of these
components use only manufacturer's specified parts.
* The parenthesized indications in the Remarks columns specify the areas. (Refer to the cover page for area.)
Parts without these indications can be used for all areas.
Part Name & Description
VARIABLE RESISTOR (S)
Ref. No. Part No. Part Name & Description
INTEGRATED CIRCUIT (S)
EVNDXAAOOB14
|¥. R, FM MPX VCO ADJ.
M7001
1. C, PLL FREQENCY
4
AN7273W
1. C, FM/AM IF AMP. DET
COMPONENT COMBINATION (S)
RVIBA1332L
1. C, FM MPX
RALO006
COMPONENT COMBINATION
MN187125STT1 IE C, MICRO COMPUTER
RL12Z003M-T
COMPONENT COMBINATION
TRANSISTOR (S)
RLA6Z002M-T
COMPONENT COMBINATION
RCDHC-278
REMOTE SENSOR
2802785FE
|TRANSISTOR
2862787L
TRANSISTOR
COIL {S)
TKSC2785YGTA
TRANSISTOR
KSC2785YGTA
TRANSISTOR
ELEXTR22MA9
COIL
KSAL175YGTA
TRANSISTOR
ELESNR22MA
COIL
KSAL175YGTA
TRANSISTOR
ELEXT101KAS
a
COIL
KSC2785YGTA
TTRANSISTOR
28C2785FE
KSC2785YGTA
28C1740SQ
TRANSISTOR
TRANSISTOR
TRANSISTOR
TRANSISTOR
2SD1862QRTV6 | TRANSISTOR
2SC1685RSTTA | TRANSISTOR
TRANSFORMER (S)
T201 RLI4B002M-2 | TRANSFORMER
T202 RLI4BO03M-Z {TRANSFORMER
T701 RFKCTCH7N-K |}POWER TRANSFORMER
Q704 KSC2785YGTA | TRANSISTOR
Qg01 KSC2785YGTA | TRANSISTOR =") apes
902, 903 |DTCL44EKT96 | TRANSISTOR CF201, 202 |RLEFETWNAOIL [CERAMIC FILTER
904, 905 |KSC2785YGTA | TRANSISTOR
0906 [prataaestP hrasiston OSCILLATOR (S)
Q907, 908 |KSC2785YGTA |TRANSISTOR T
+—
SVQ@SU722-S
OSCILLATOR
DIODE (S) EFOGC4194T4 [OSCILLATOR
|
D201 18S291TA DIODE ‘sry
D302 1SS254TA DIODE
D701 1SR352001B =| DIODE A RSLOOS6-F DISPLAY
D703 MA4068M DIODE
D705,
706
=|
1SR35200TB
=
DIODE
lA
ce
SWITCH(ES)
D707 MA4240H DIODE
la PRESET UP
Part Name & Description
EVQ21405R SW, CLOCK SET
EVQ21405R SW, RECALL
Teve2i405r —_|SH, CANSEL
EVQ21405R
[se POWER
CONNECTOR (S)
RJUOOSKOOGM1 |SOCKET (6P)
|RJUOO3KDO8M1 | SOCKET (8P)
RJTOOSKOOGM1 |CONNECTOR (6P)
RJTOO3KOO8M1 ae (8P)
VARIABLE CAPACITOR
:
RCVIOAFIT-S | TRIMMER CAPACITOR
JACK (S)
RJH4202M ANT. TERMINAL BOARD
RJHA405-1M |ANT. TERMINAL BOARD
‘[paosso11- 1 |CONTROL TERMINAL
{—
——
wadisom (DIODE £VQ21405R
D709 MA4O47MTA DIODE ]evazi405R —_[SR, PRESET DORN
D711-718 | 1SS254TA coe EVO21405R
D9Ot 1ss291T4 [DIODE EVQ21405R
p902, 903 |1SS254TA [DIODE EVQ21405R
Daog 1SS254TA aoc EVQ21405R
Dalz 1SS254TA [DIODE EVQ21405R
D913 1SS254TA EvO21405R
[ptoDE
(GC)
+
~17-
EVQ21405R
—18—

| ST-CH7L
ST-CH7L
* Resistance values are in ohms, unless specified otherwise, 1K=1,000(OHM) , 1M=1, 000k(OHM)
| Notes : * Capacity valuse are in microfarads (uF) unless specified otherwise, P=Pico-farads (pF) F-Farads (F) |
ERDS2TJ103
Values & Remarks Values & Remarks
ERDS2TJ222 1/48 2.2K
RESISTORS
ERDS2TJ562
ERDS2TJ104 1/4¥ 100K
ERDS2TJ681
ERDS2TJ122 1/4W¥ 1.2K
ERDS2TJ562
i/4AW 5. 6K
ERDS2TJ102
ERDS2TJ104 1/4¥_ 100K
ERDS2TJ103
1/aW 10K
ERDS2TJ682T
}ERDS27J104 1/4¥ 100K
ERDS2TJ561
1/4W 560
ERDS2TJ390
he
{ERDS2TJ563 1/AWOSGK
ERDS2TJ102
1/aW 1K
{enosense72t
ERDS2TJ393
1/4W
ERDS2TJ102 CAPACITORS
ERDS2TJ103
1/4W
ERDS2TJ104
ERDS2TJ102
1/4W
ERDS2TJ102 ECEALEK4R7 25y. 4.
1/4¥
ERDS2TJ103
ECKRIH1032ZF5 | SOV 0. 01U
1/48
ECEAICU101 16V 100U
| 1/4W
ERDS2TJ274
ERDS2TJ5R6
ECCRIHO80DC5 ; SOV 8p
1/4W
TERDS2TJ152
ECCRIHLSOKCS [ Sov. —15P
t
1/4W
ERDS2TJ331
ECKRIHI1O32F5 | SOV 0. 01U
1/4W
ERDSLFWJi51T
ECEALCK100B 16V 100
ERDS2TJ331
1/4¥
ERDS2TJ2R2T
ECBTICLO3NSS | 16V 0. 01U
ERDS2TJ474
1/4¥
[ERDS2TJS61
[Ecxrumoszes SOV 0. G1U
ERDS2TJ331 1/4¥
ERDS2TJ331
ERDS2TJ104
ERDS2TJ272T
1/4W 3. 3K
ERDS2TJ561
ERDS2TJ101 1/48 = 100
ERDS2T562 | 1/4¥ 5. 6K
ERDS2TJIRO | 1/4W 1.0
ERDS2TJ100 | 1/4W 10
ERDS2TJ100
ERDS2TJ470 | 1/4W 47
BRDS2TJ223 | 1/4#
ECBT1HI02KB5 | 50V 1000P
ECKRIHLO3ZF5 | SOV 0. O1U
TECBTLHO2KBS | SOV 1000P
SOV 0. O1U
_jERDS21J470 1/4W
ECEAQJUIO1B | 6.3V 100U
10K
ERDS2TJ103 1/40
ECEALEK3R3B 25V 3. BU
360
ERDS2TJ223 1/48
lll 25V 0. OU
8. 2K
ERDS2TJ470 1/44
ECKRIH103ZF5 | SOV 0. 01U
ERDS2TJ103 1/44
ECKT1H2232F 50V 0.022U
ECCR1H101K5 Sov. 100P
ERDS2TJ333 1/4"
ERDS2TJ103 1/4W
ECEA1HKO10B ov 1U
ERDS2TJ223 1/4W
16V. 10
SOV 0. 01U
jenos2Tsez2 1/48
[ERDS2TJ122 1/48
ERDS2TJ822
ERDS2TJ103 1/4"
25V 0.047U
16V 0.010
ERDS2TJ102 1/48
SOV. —«18P
ERDS2TJ103 1/48
ECEAICK100B 16V 100
ERDS2TJ182
ERDS2TJ393 1/48
ECBT1E2232F 25V 0. 022U
ERDS2TJ104 1/4W
ECEALHKO10B S0V 1U
ERDS2TJ472 1/48
ECBTIE2232F | 25V 0.022U
ERDS2TJ122
ERDS2TJ102
ECEAQJU102 6.3V 10000
ERDS2TJ822
16V—10U
R261 ERDS2TJ102
R262 ERDS2TJ332
ERDS2TJS62
25V_ 0. O1U
ERDS2TJ393
SOV. 1000P
r2e3—ERDSZT153 | 1/4W 15K
p64 —feRDSzTJi02 | 1/4W 1K
ERDS2TJ182
—~19—
SOV 0. 47U
Val:
ECEA1HKR33 50V
ECEA1HKO10B
25V
ECFRIE272KR
ECEAICK100B
ECKR1H1032F5
ECEAICU102B
ECKR1H1032F5
ECEA1AU221
CEAIEK3R3B | 25V
CBAIHG81KBS | SOV 680P
= =
ixr]
—20—

ST-CH7L
|
|
ST-CH7L
Val
ECEAIHKR33 | 50V 0.33
ECEAIHKO10B | 50V IU
ECFRIE1O3KR | 25V 0. O1U
BCEAIHKO10B | SOV 1U
ECFRIE272KR | 25V 2700P
ECEAICK100B 10U
ECKRIH1O3ZF5 0. 01
ECEAICUI02B 1000U
ECKRIHIO3ZF5 0. OU
BCEAIAU221 2200
ECKR2H102ZF5 | 500V 1000P
ECEAIVU331B | 35V 330U
ECKRIHIO3ZF5 | SOV 0. O1U
ECEAICUIO! | 16V 100U
ECKR2H1022F5 | 500V 1000P
ECEAIHU220. | SOV 22U
ECEAIHKD10B | SOV 1U
ECKRIHIO3ZF5 | 50V 0. 01U
ECFRIHIO4ZF | SOV 0.1U
ECEAQJUIO2 | 6.3V 1000U
Part Name & Description Part Name & Description
RFKJTCH7LE-K [CASSIS ASS’ Y
SHG1654 [FOOT
[RGUOSS3-K BUTTON, PRESET
RGUOS54-K | BUTTON, TUNING
RGUOS55-A | BUTTON, TIMER
TRGUOSS6-K BUTTON, POWER
RGUOS57-K BUTTON, BAND SELECT
REKGTCH7LE-K |FRONT PANEL ASS’ Y
RFKGTCH7LGCK {FRONT PANEL ASS’ Y
RMNO123 ‘(FL HOLDER
XTB3+8JF2 [SCREW
|CABI NET PARTS
RHD30007 (SCREW
{eewoise-x [CABINET
RGRO1I6A-C |REAR PANEL
RGROLI6A-D1 {REAR PANEL
RMRO427 [HOLDER
SHEI70-2 [SPACER
XTBS26+8J (SCREW
XTBS3+8JFZ1 [SCREW
XTB3+12JFZ
+
ECEAQJK330 6.3V = 33U
ECBTICIOaNSS
|
_16V_
0.010
@
CABINET
PARTS
LOCATION
ECEAIHKOR1 0.1U
ECEALEKSR3B 3. 3U
Printed in Japan
gO
—21-—
F910410300FF/HH/KK/MT

ORDER NO. AD9104109A2
Service Manual
Tuner
LW/MW/FM Stereo Tuner
Color
( Please file and use this manual together with the ~) (K) bie Black Type
service manual for model No. ST-CH7L Order No.
AD9104083C8. Area
This service manual indicates the main differences
between; Original ST-CH7L (E) and ST-CH7L (EG). Country re
aa f ea Color
Refer to the Schematic Diagram, Block Diagram, Code
_ Circuit Board and Wiring Connection Diagram of this
Service Manual. (EG) F.R. Germany and Italy | (K) |
pee baleen /
System: SC-CH7
Because of unique interconnecting cables,
when a component requires service, send or
bring in the entire system.
@ CHANGE IN REPLACEMENT PARTS LIST
Note: Mentioned in this parts list of cabinet parts are only those different from Model No. ST-CH7L (E); all other cabinet
parts
are
the
same
as
for
ST-CH7L
(E),
and
accessories
are
only
those
different
from
Model
No.
SU-CH7
(E)
Order No. AD9104082C8; all other accessories are the same as for SU-CH7 (E).
For the electrical parts, see page 11 through 14 of this service manual for ST-CH7L (EG).
®ST-CH7L (Page 21 of service manual.)/SU-CH7 (Page 36 of service manual.)
r
Change of Part No. :
Ref. No. Part Name & Description Remarks
LL ST-CH7L (E) ST-CH7L (EG)
CABINET PARTS
3 RGRO0116A-C RGR0116A-E1 | REAR PANEL
| PACKING MATERIAL
PI RPG0O925 RPG1045 PACKING CASE SYSTEM
ACCESSORIES |
f Al RQF1125 RQF1127 INST. MANUAL ASS’Y
L A1-1 RFKSUCH7E-K RQT1035-D INSTRUCTIONS MANUAL
System | Tuner__| Ampiir [GD Player
SC-CH7 ST-CH7L SU-CH7 SL-CH7
Technics
RS-CH7 SB-CH7

ST-CH7L
m@ MEASUREMENTS AND ADJUSTMENTS
FM ADJUSTMENT
Control positions and equipment used
@FM signal generator (FM-SG)
Stereo modulator
eDistortion analyser
DC electronic voltmeter (EVM)
Frequency counter
Choke coil (100 UH)
Resistor (100 kQ)
Note: For L321, L322, L324, Z321, 2251 (AM-ANT/OSC) and Z202 (AM-IFT), they are supplied as adjusted parts. So, do not turn the cores of
the parts.
It is not necessary to adjust the AM circuit.
FM STEREO DISTORTION ADJUSTMENT
1.Test equipment connection is shown in figure.
2. Set the unit to “FM” mode.
3. Set the radio frequency display and signal generator to
100.10 MHz.
4. Adjust L1 so that the distortion factor of L-CH is minimized.
§. Make sure that the distortion factors of L-CH and R-CH are
nearly the same with each other to minimum.
FM SIGNAL GENERATOR CONDITION
Modulation Stereo “L’’ mode or “R”
mode 45%, Pilot 10%
Modulation frequency
Output level
ajo
FM ANT — Output Distortion analyser
9
Notes: ud
1. The adjusting screwdriver used should be made of resin.
2. L1 should be rotated no more 1/4 turn (90 deg.) on either side.
Stereo modulator
Output mode... L or R
e ADJUSTMENT POINTS
Addition
----, i
1 FM '
| Stereo |
| distortion |
i ;
LINE OUT LINE OUT
(Lech) (Reh)
FM mono
distortion
FM offset
PLL clock Frequency
FM MPX VCO
(ISkHz}

ST-CH7L
ST-CH7L
||
BLOCK
DIAGRAM
RVIBAI332L
Q302
JK7OI
FM
MONO
DISTORTION
adj.
[)
@R ch out
TP202
TP2oO}
FM
MPX
D302
00
T201,202
ANT273W
4
i
0304
FM
ANT
+f
GB)
L1C201
|
Y
Zio
u
FM/AM
IF
AMP
DET
‘ 2 14
FM
FRONT
END
CF201
CF
202
8
jo
fie
fiz
|r
=|
ee
ees
I
aD ao
ge
ga
Q201,202
a!
,
Lr
1c201
FM
vO lFM/AM FM |
ea tea !
zee i eT oon
ee
ee ed re he ce
5
G5) oat | Q301
Buffer
(AM) L ch out
: oe
— on awe
Q256
MW/LW
Signal
Loop filter receive
XI0l
detector
Hl
CTIO!
(7.2MHz)
z90l
pr
Q
a
2808
fs
|
REMOTE
Q207~209
u
2
eu
ta
Remote
7
CONTROL
pecan
oe
celal
PLL
FREQUENCY
control
SENSOR
Om — Oe
pXOUT XIN PO! LW PD2 FMIN 6
AM IN
CE CL DATA
KEY MATRIX L
[ ss ae 2 a ae ae
B
WW
(AM) GB) FM/AM
Power Supply
(FM) GB) Selector
SYNTHESIZER
| 22 24 31
Q907,908
Switching
(power)
—_—ld POWER
ee Cae eee on ee |
CE
sBTI sBol
sD
POWER
RST
MUTE
STEREO
MONO
INT
POWER
Q902~905
I Lie
7
\
: Wn f KEY2 DOWN
oer.
(ATUNING)
if
|
|
MNIS7I25STTI
8)
ees
901 $905
|
|
;
B.DATA
| wa \ | MICROCOMPUTER
I(WPRESET)
|
(MEMORY)
|
(¥
TUNING)
|
|
(CONTROLLER)
46)|
B.
GND
|
$902
$904
$906
|
l
SEGO
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SEGI5,
P70
DGTO~DGT6
oe
Pa
eee
ee
Ne
+
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a
2
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|
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36—«
37
2 3
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38
44
64
| (BAND) Heeb
$903 '
| oa | Pye
0
I 2 | | |
| | \
| ! |
es _J
|(4SELECT)
|
(CLOCK
SE
2
| $907
|
a
Q703
D701,705
T701
\
Bz
FL
DISPLAY
---
nc
l(w
SELECT)
(RECALL)
|
| $908 soil
re
oe
be
!
|
|
(TIMER
SET)
(CANCEL)|
(POWER)
Regulator
|
$909 $913
| v4 va ‘S Note:
e al lpeciene te ma
—
are
ee
|—P—:FMSIGNAL
|
I
onag>
=
FM
OSC
!
&
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1
2
3 4
5
6
7
Notes:
eS901,902
:
Preset
channel
switch.
(S901:
Up,
$902:
Down)
ZIOl_
FM
FRONT
END
PACK(SNVFE337601)
Ban)
eS903
:
Band
select
switch.
aan
|
2Sk193
OR
28K241
2SC
2668
:
.
a
ooo
oo
FM
RF
AMP
FM
MIXER
ifK
eS904
;
Memory
switch.
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ANT
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Switch.
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$822
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TO
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Timer
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S912
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3
2SC2787LTA
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$913
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BUF
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x
:
:
AM
ANT
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FM
OSC
a
j
ee
&8
|
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indicated
voltage
values
are
the
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values
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the
unit
measured
by
ee
maT
ale
BF
<
a *
if
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c:
al
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206
C226
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the
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|
Sea
vier
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i
—-
i
2UH
i
standard.
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there
may
exist
some
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in
the
voltage
values,
B
AM
ae
| |
:
2
Sag
SL
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depending
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the
internal
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circuit
tester.
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5
Eat
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|
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Deg
|
a
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(
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MUTING
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8)
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28
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safety
notice
:
.
bat
er
|
|
3
Components
identified
by
A
mark
have
special
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important
hee
pT
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|
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0257
PLL
clock
=a
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~254
.
Liv
1K
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ia
for
safety.
When
replacing
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these
components,
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Me
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2785YGTA
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AMP(LW/MW
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aa
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This
schematic
diagram
may
be
modified
at
any
time
with
the
I
ye
|
azss
‘ B
—
jf
development
of
new
technology.
Sige
:
MW3
ened
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0255,
256
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|
7
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Secondary
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can
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taking
care
during
repair.
bagi
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|
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Cover
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parts
boxes
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Mepe
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Ae
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the
work
table.
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YsoBt—
Psofs
4
ANY
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oh
Ue
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t
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PUMA
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IC
or
LSI
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directly.
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To SL-CHT/
SU“CHT

ST-CH7L ST-CH7L
m REPLACEMENT PARTS LIST
Notes : * Important safety notice:
Components identified by A\ mark have special characteristics important for safety. When replacing any of these
components use only manufacturer s specified parts.
* The parenthesized indications in the Remarks columns specify the areas. (Refer to the cover page for area.)
Parts without these indications can be used for all areas.
hi = : wae den ol i is ies . aoa vielli
V.R, FM MPX VCO ADJ.
INTEGRATED CIRCUIT (S)
EVNDXAAOOB14
COMPONENT COMBINATION (S)
LM7001
AN7273W
RVIBA1332L
MN187125STT1 1. C, MICRO COMPUTER
1. C, PLL FREQENCY
1. C, FM/AM IF AMP. DET
COMPONENT COMBINATION
COMPONENT COMBINATION
COMPONENT COMBINATION
COMPONENT COMBINATION
REMOTE SENSOR
SNVFE337601
RL122003M-T
RLA6Z002M-T
SLA4Z13M-2
TRANSISTOR
TRANSISTOR
TRANSISTOR
COIL(S)
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KSALI75YGTA | TRANSISTOR
KSAL170YGTA | TRANSISTOR
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RLFFETNGAOZL |CERAMIC FILTER
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D302 1SS254TA | DIODE
D701 1SR352001B _ |DIODE A
MA4O68M =—_|DIODE
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MA4240H [DIODE
MA4150M [DIODE
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SWITCH (ES)
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$902 fares SW, PRESET DOWN
EVQ21405R SW, BAND
EVQ21405R SW, MEMORY
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VARIABLE RESISTOR(S)
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SOCKET (6P)
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SOCKET (8P)
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CONNECTOR (6P)
RJT003K008M1
CONNECTOR (8P)
VARIABLE CAPACITOR
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TRIMMER CAPACITOR
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